1. Field of the Invention
The present invention relates to a substrate holder and to a reaction apparatus for forming a film or etching the same, more specifically, to an apparatus that forms an insulating film or the like by using reaction gas and heating a substrate or performs etching, and a substrate holder for holding a substrate to be processed.
2. Description of the Prior Art
A CVD apparatus is a useful apparatus in forming a SiO.sub.2 film, a PSG film, a BSG film, a BPSG film, a Si.sub.3 N.sub.4 film, an amorphous Si film, a polycrystalline Si film, a W film, a Mo film, a WSi.sub.2 film, a MoSi.sub.2 film, an Al film or the like in manufacture of a semiconductor device.
Conventional CVD apparatus is classified by its means for activating reaction gas as follows:
1 thermal CVD apparatus, PA1 2 light-assisted CVD apparatus, and PA1 3 plasma-assisted CVD apparatus.
The thermal CVD apparatus has heating means for supplying heat energy to activate the reaction gas, and is classified either as a low pressure type or a normal pressure type, depending on the pressure employed. Further, the apparatus is classified as a low temperature type or a high temperature type depending on the substrate temperature, and furthermore, is classified as a resistance type, an induction heating type or a lamp heating type, depending on the heating means. Further, it is classified as a hot wall type or a cold wall type, depending on the location of installation of the heating means.
A light-assisted CVD apparatus includes light irradiation means for supplying energy to reaction gas so as to active the reaction gas by irradiating the reaction gas with ultraviolet rays, and is able to form a film under low pressure or high pressure and at a low temperature.
A plasma-assisted CVD apparatus uses plasma generating means for activating reaction gas directly or indirectly using AC power or a magnetic field, and the plasma is generally generated under low pressure and at a low temperature. The plasma-assisted CVD apparatus is classified, depending on the plasma generating means, as a parallel plate type for activating reaction gas directly by radiation of high-frequency power or an ECR type for supplying energy to electrons by high-frequency power and a magnetic field and activating the reaction gas indirectly with these electrons.
An etching apparatus, in particular a dry etching apparatus, is a useful apparatus for manufacturing a semiconductor device in case of precise etching of a SiO.sub.2 film, a PSG film, a BSG film, a BPSG film, a Si.sub.3 N.sub.4 film, an amorphous Si film, a polycrystalline Si film, a W film, a Mo film, a WSi.sub.2 film, a MoSi.sub.2 film, an Al film or the like, and is classified in a manner similar to the CVD apparatus described above.
In the CVD apparatus and the etching apparatus described above, a substrate holder for fixing a substrate to be processed is provided with a mechanical chuck, a vacuum chuck or an electrostatic chuck.
Since only a substrate and its vicinity are heated in a cold wall type apparatus for manufacturing a semiconductor, it provides the advantage that the reaction is localized, thus preventing reaction products from adhering to an inner wall of the reaction chamber. The heating mans is provided below the substrate holder in the form of an RF electrode or the like.
In the case of the cold wall type, the substrate on the substrate holder is heated through an RF electrode or the like. Thus, although there is the advantage that the large thermal capacity of the RF electrode resists fluctuation of the substrate temperature once attained, a large amount of electric power is consumed in heating the substrate. Further, when it is desired to change the substrate temperature, the substrate holder cannot be brought to the new temperature in a short period of time and requires a long time until the substrate temperature is stabilized at the new temperature.
Furthermore, since reaction products are produced within the apparatus for forming a film and the etching apparatus described above, they adhere to the inner wall of the reaction chamber as particles or the like. Accordingly, it is required that these reaction products be periodically removed. As a result, the throughput is decreased and a great amount of labor and cost are required.